63hz

Hey guys
Im currently upgrading my HD24 rig
i record live bands at pubs and clubs
and so far have just been using direct outs
they've been good at some venues but horrible at others
so i want to put in some pre's and some monitoring
I realize there is alot about hd24s on this forum and i've spent the last few days reading over it, but couldn't find anything that answered my questions specifically
my plan is to run
Y-split xlr of foh console into
3 racks of digimax d8 adat into
hd24 record
hd24 line outs into speck x-sum (some less important channels being stereod)
x-sum into rackmount cd burner for backups (also thinking of a flash recorder)
now i could also use the lines out of the digimax's into the xsum and that way if hd24 lost power they would pass audio through to the x-sum and backup recorder

my biggest question is how to set up the adat. do i need an external word clock?
and if anyone has any better suggestions or ideas i'd love to hear.
the only item i have currently is the hd24
thanks